Antiplatelet and Anticoagulant Drugs Flashcards
aspirin drug name
- acetyl-salicylic acid (ASA)
aspirin at low doses MOA
- irreversibly acetylates COX1
- inhibits generation of TXA2
higher doses of aspirin MOA
- inhibit COX2
aspirin used for
- primary and secondary prevention of arterial blockages
examples of arterial blockages
- MI
- stroke
- PVD
aspirin side effects
- GI bleeding
- provoke asthma
- kidney damage
aspirin contraindicated in which population
- children and teenagers with chickenpox or flu symptoms
GI bleeding of aspirin
- inflammation
- peptic ulcer disease
at high doses aspirin can cause
- salicylate toxicity
- tinnitus
warfarin biochemical effect
- vitamin K antagonist
warfarin MOA
- blocks reduction of Vit K
- limits carboxylation of coagulation factors
what stage of vitamin K does warfarin block?
- NEW VITAMIN K
time of effect of warfarin
- not immediate
first three days of warfarin
- brings to hyper coagulable state
how to reverse warfarin hyper coagulable state
- bridging anticoagulant therapies
hyper coagulable state worse in patients with
- protein C deficiency
- vitamin K deficiency
warfarin used for treatment of
- VTE
warfarin used for prevention of
- thrombosis on mechanical heart valves
- embolic strokes in patient with Afib
how do we measure warfarin dosing
- measure INR weekly to start
what do we want the IR to be for warfarin
- between 2-3
drug food interactions of warfarin
- maintain steady amount of vitamin K containing foods
drug-drug interactions of warfarin
- drugs that interfere with CYP enzymes
- antibiotics
monitoring warfarin at therapeutic levels
- follow PT/INR
warfarin at toxic levels has what effect on the aPTT
- prolonged
warfarin effect on PFA-100
- no effect
side effects of warfarin
- alopecia
- osteoporoesis
- bleeding
- warfarin skin necrosis
how does someone get warfarin skin necrosis?
- vitamin K deficient
- protein C deficiency without bridging
warfarin skin necrosis effects the
- microvascular thrombosis
- fatty tissues
warfarin and pregnancy
- warfarin is a teratogen
warfarin and lactating women
- okay for lactating women
warfarin reversal
- vitamin K
- prothrombin complex concentrates (PCC)
PCC composed of
- factor 2, 7, 9, 10
composition of animal derived heparin
- polysaccharide with variable sulfated residues
variation in polysaccharide sequence and length and degree of sulfation in heparin make it
- heterogenous
- each dose different and impacts each individual differently
heparin binds
- antithrombin
heparin inactivates
- factor Xa, IXa, XIa
full length heparin forms a complex with
- thrombin and antithrombin
how long does heparin have to be to inactivate thrombin
- 18 sugars long
unfractionated heparin must be given in which form
- IV
- SQ
unfractionated heparin must be given in which setting
- the hospital
what do you follow in heparin monitoring?
- aPTT
- anti-Xa level
heparin effect on TCT
- prolonged TCT
heparin effect on PT
- normal as long as it is not a large dose
how is the Xa level measured with heparin
- rate of conversation of a substrate into a colored byproduct
- add patient’s plasma to mix and see if it slows the conversion to a colored solution
- decrease in rate is the Anti-Xa level
heparin side effects
- bleeding
- osteoporosis with long term use
- hyperkalemia
- development of heparin induced thrombocytopenia
heparin antidote
- protamine sulfate
protamine sulfate MOA
- positively charged
- neutralizes negatively charged heparin
low molecular weight heparin compared to unfractionated heparin
- smaller
- about 1/3 the size
drug name of LMWH
- enoXaparin
enoxaparin given via
- SQ
bioavailability of enoxaparin
- immediately bioavailable
enoxaparin can be used to
- bridge warfarin
enoXaparin MOA
- inactivates Xa
why can enoXaparin not inactivate thrombin
- it is too short
LMWH effect on PT
- no effect
LMWH effect on aPTT
- no effect
what do you follow with patients on LMWH
- Anti-Xa levels
antidote for LMWH
- no antidote
LMWH uses
- VTE treatment and prophylaxis
- VTE associated with cancer
treatment of LMWH for VTE
- done at home via SQ
- especially pregnant women
LMWH side effects
- bleeding
- pain at injection site
- can’t use in dialysis
- HIT
if HIT, what happens with LMWH
- can’t use
Fondaparinux complex
- pentasaccharide part of heparin
- don’t use in kidney failure
Fondaparinux mechanism
- bind to antithrombin
- inactivate Xa
Fondaparinux and HIT
- does not cause HIT
- may worsen HIT
Fondaparinux route of administration
- SQ
Fondaparinux antidote
- no antidote
DOACs
- direct oral anti coagulants
Dabigatran MOA
- inactivates thrombin directly
Dabigatran used for
- prevention of stroke in Afib patients
- treatment of VTE
Dabigatran not used for
- heart valves
Dabigatran effect on TT
- prolongs TT because it inactivates thrombin
Dabigatran adverse effects
- bleeding
- GI upset
- renal clearance
Dabigatran mechanism of entry
- oral
Dabigatran antidote
- Idarucizumab
- Prax-bind
Argatroban mechanism of entry
- IV
Argatroban MOA
- direct thrombin inhibitor
Argatroban used for patients with
- HIT
Argatroban metabolized how
- hepatically
Argatroban effect on aPTT
- prolongs
Argatroban effect on PT/INR
- prolongs
Argatroban effect on TCT
- prolongs
Argatroban how to monitor
- use aPTT
RivaroXaban, ApiXaban, and EdoXaban MOA
- inactivates Xa
- binds Xa inhibitor competitively with Xa
- GLA domain removed to prevent anticoagulant effect
RivaroXaban, ApiXaban, and EdoXaban cleared by
- kidney
- chemical degradation
DOACs advantages over warfarin
- fewer intracranial bleeds
DOACs disadvantages compared to warfarin
- not effects in preventing stroke in patients with mechanical heart valves